Completing and signing Form I-864 makes you the sponsor. I134 Affidavit of Support.Form to sponsor a visa applicant and show they will not become a public charge while in the U.S.. N-400, Naturalization Application. In this guide, we will explain who needs to complete Form I864, when to file it, and how to fill out Form I864 stepbystep. If you are applying for a family preference visa, you will need to file Form I-130, Petition for Alien Relative, and Form I-864, Affidavit of Support. The purpose of the Affidavit is to assist consular officers in determining whether a visa applicant will have adequate means of financial support in the US. A) Complete an Affidavit of Support form and; b) Gather evidence of their finances and other supporting documents (See Step 5). If you are coming to the United States on a temporary visa, you may need to prove financial support. A sponsor can file the I-134 form. Please complete the Opt-out Credit Form for F1 International Students.